Fabric 1.0原始碼分析(5)Chaincode（鏈碼）體系總結

尹成發表於2018-05-20
原始碼AI
# Fabric 1.0原始碼筆記 之 Chaincode（鏈碼）

## 1、Chaincode概述

Chaincode，即鏈碼或智慧合約，程式碼分佈在protos/peer目錄、core/chaincode和core/common/ccprovider目錄，目錄結構如下：

* protos/peer目錄：
    * chaincode.pb.go，ChaincodeDeploymentSpec、ChaincodeInvocationSpec結構體定義。
* core/chaincode目錄：
    * platforms目錄，鏈碼的編寫語言平臺實現，如golang或java。
        * platforms.go，Platform介面定義，及部分工具函式。
        * java目錄，java語言平臺實現。
        * golang目錄，golang語言平臺實現。
* core/common/ccprovider目錄：ccprovider相關實現。

## 2、protos相關結構體定義

### 2.1、ChaincodeDeploymentSpec結構體定義（用於Chaincode部署）

#### 2.1.1 ChaincodeDeploymentSpec結構體定義

```go
type ChaincodeDeploymentSpec struct {
    ChaincodeSpec *ChaincodeSpec //ChaincodeSpec訊息
    EffectiveDate *google_protobuf1.Timestamp
    CodePackage []byte //鏈碼檔案打包
    ExecEnv ChaincodeDeploymentSpec_ExecutionEnvironment //鏈碼執行環境，DOCKER或SYSTEM
}

type ChaincodeDeploymentSpec_ExecutionEnvironment int32

const (
    ChaincodeDeploymentSpec_DOCKER ChaincodeDeploymentSpec_ExecutionEnvironment = 0
    ChaincodeDeploymentSpec_SYSTEM ChaincodeDeploymentSpec_ExecutionEnvironment = 1
)
//程式碼在protos/peer/chaincode.pb.go
```

#### 2.1.2、ChaincodeSpec結構體定義

```go
type ChaincodeSpec struct {
    Type ChaincodeSpec_Type //鏈碼的編寫語言，GOLANG、JAVA
    ChaincodeId *ChaincodeID //ChaincodeId，鏈碼路徑、鏈碼名稱、鏈碼版本
    Input *ChaincodeInput //鏈碼的具體執行引數資訊
    Timeout int32
}

type ChaincodeSpec_Type int32

const (
    ChaincodeSpec_UNDEFINED ChaincodeSpec_Type = 0
    ChaincodeSpec_GOLANG ChaincodeSpec_Type = 1
    ChaincodeSpec_NODE ChaincodeSpec_Type = 2
    ChaincodeSpec_CAR ChaincodeSpec_Type = 3
    ChaincodeSpec_JAVA ChaincodeSpec_Type = 4
)

type ChaincodeID struct {
    Path string
    Name string
    Version string
}

type ChaincodeInput struct { //鏈碼的具體執行引數資訊
    Args [][]byte
}
//程式碼在protos/peer/chaincode.pb.go
```

### 2.2、ChaincodeInvocationSpec結構體定義

```go
type ChaincodeInvocationSpec struct {
    ChaincodeSpec *ChaincodeSpec //參考本文2.2
    IdGenerationAlg string
}
//程式碼在protos/peer/chaincode.pb.go
```

## 3、ccprovider目錄相關實現

### 3.1、ChaincodeData結構體

```go
type ChaincodeData struct {
    Name string
    Version string
    Escc string
    Vscc string
    Policy []byte //chaincode 例項的背書策略
    Data []byte
    Id []byte
    InstantiationPolicy []byte //例項化策略
}

//獲取ChaincodeData，優先從快取中讀取
func GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error)
//程式碼在core/common/ccprovider/ccprovider.go
```

func GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error)程式碼如下：

```go
var ccInfoFSProvider = &CCInfoFSImpl{}
var ccInfoCache = NewCCInfoCache(ccInfoFSProvider)

func GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error) {
    //./peer/node/start.go: ccprovider.EnableCCInfoCache()
    //如果啟用ccInfoCache，優先從快取中讀取ChaincodeData
    if ccInfoCacheEnabled {
        return ccInfoCache.GetChaincodeData(ccname, ccversion)
    }
    ccpack, err := ccInfoFSProvider.GetChaincode(ccname, ccversion)
    return ccpack.GetChaincodeData(), nil
}
//程式碼在core/common/ccprovider/ccprovider.go
```

### 3.2、ccInfoCacheImpl結構體

```go
type ccInfoCacheImpl struct {
    sync.RWMutex
    cache map[string]*ChaincodeData //ChaincodeData
    cacheSupport CCCacheSupport
}

//構造ccInfoCacheImpl
func NewCCInfoCache(cs CCCacheSupport) *ccInfoCacheImpl
//獲取ChaincodeData，優先從c.cache中獲取，如果c.cache中沒有，則從c.cacheSupport（即CCInfoFSImpl）中獲取並寫入c.cache
func (c *ccInfoCacheImpl) GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error)
//程式碼在core/common/ccprovider/ccinfocache.go
```

func (c *ccInfoCacheImpl) GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error) 程式碼如下：

```go
func (c *ccInfoCacheImpl) GetChaincodeData(ccname string, ccversion string) (*ChaincodeData, error) {
    key := ccname + "/" + ccversion
    c.RLock()
    ccdata, in := c.cache[key] //優先從c.cache中獲取
    c.RUnlock()

    if !in { //如果c.cache中沒有
        var err error
        //從c.cacheSupport中獲取
        ccpack, err := c.cacheSupport.GetChaincode(ccname, ccversion)
        c.Lock()
        //並寫入c.cache
        ccdata = ccpack.GetChaincodeData()
        c.cache[key] = ccdata
        c.Unlock()
    }
    return ccdata, nil
}
//程式碼在core/common/ccprovider/ccinfocache.go
```

### 3.3、CCCacheSupport介面定義及實現

#### 3.3.1、CCCacheSupport介面定義

```go
type CCCacheSupport interface {
    //獲取Chaincode包
    GetChaincode(ccname string, ccversion string) (CCPackage, error)
}
//程式碼在core/common/ccprovider/ccprovider.go
```

#### 3.3.2、CCCacheSupport介面實現（即CCInfoFSImpl結構體）

```go
type CCInfoFSImpl struct{}

//從檔案系統中讀取並構造CDSPackage或SignedCDSPackage
func (*CCInfoFSImpl) GetChaincode(ccname string, ccversion string) (CCPackage, error) {
    cccdspack := &CDSPackage{}
    _, _, err := cccdspack.InitFromFS(ccname, ccversion)
    if err != nil {
        //try signed CDS
        ccscdspack := &SignedCDSPackage{}
        _, _, err = ccscdspack.InitFromFS(ccname, ccversion)
        if err != nil {
            return nil, err
        }
        return ccscdspack, nil
    }
    return cccdspack, nil
}

//將ChaincodeDeploymentSpec序列化後寫入檔案系統
func (*CCInfoFSImpl) PutChaincode(depSpec *pb.ChaincodeDeploymentSpec) (CCPackage, error) {
    buf, err := proto.Marshal(depSpec)
    cccdspack := &CDSPackage{}
    _, err := cccdspack.InitFromBuffer(buf)
    err = cccdspack.PutChaincodeToFS()
}
//程式碼在core/common/ccprovider/ccprovider.go
```

### 3.4、CCPackage介面定義及實現

#### 3.4.1、CCPackage介面定義

```go
type CCPackage interface {
    //從位元組初始化包
    InitFromBuffer(buf []byte) (*ChaincodeData, error)
    //從檔案系統初始化包
    InitFromFS(ccname string, ccversion string) ([]byte, *pb.ChaincodeDeploymentSpec, error)
    //將chaincode包寫入檔案系統
    PutChaincodeToFS() error
    //從包中獲取ChaincodeDeploymentSpec
    GetDepSpec() *pb.ChaincodeDeploymentSpec
    //從包中獲取序列化的ChaincodeDeploymentSpec
    GetDepSpecBytes() []byte
    //校驗ChaincodeData
    ValidateCC(ccdata *ChaincodeData) error
    //包轉換為proto.Message
    GetPackageObject() proto.Message
    //獲取ChaincodeData
    GetChaincodeData() *ChaincodeData
    //基於包計算獲取chaincode Id
    GetId() []byte
}
//程式碼在core/common/ccprovider/ccprovider.go
```

#### 3.4.2、CCPackage介面實現（CDSPackage）

```go
type CDSData struct {
    CodeHash []byte //ChaincodeDeploymentSpec.CodePackage雜湊
    MetaDataHash []byte //ChaincodeSpec.ChaincodeId.Name和ChaincodeSpec.ChaincodeId.Version雜湊
}

type CDSPackage struct {
    buf []byte //ChaincodeDeploymentSpec雜湊
    depSpec *pb.ChaincodeDeploymentSpec //ChaincodeDeploymentSpec
    data *CDSData
    datab []byte
    id []byte //id為CDSData.CodeHash和CDSData.MetaDataHash求雜湊
}

//獲取ccpack.id
func (ccpack *CDSPackage) GetId() []byte
//獲取ccpack.depSpec
func (ccpack *CDSPackage) GetDepSpec() *pb.ChaincodeDeploymentSpec
//獲取ccpack.buf，即ChaincodeDeploymentSpec雜湊
func (ccpack *CDSPackage) GetDepSpecBytes() []byte
//獲取ccpack.depSpec
func (ccpack *CDSPackage) GetPackageObject() proto.Message
//構造ChaincodeData
func (ccpack *CDSPackage) GetChaincodeData() *ChaincodeData
//獲取ChaincodeDeploymentSpec雜湊、CDSData、id
func (ccpack *CDSPackage) getCDSData(cds *pb.ChaincodeDeploymentSpec) ([]byte, []byte, *CDSData, error)
//校驗CDSPackage和ChaincodeData
func (ccpack *CDSPackage) ValidateCC(ccdata *ChaincodeData) error
//[]byte反序列化為ChaincodeDeploymentSpec，構造CDSPackage，進而構造ChaincodeData
func (ccpack *CDSPackage) InitFromBuffer(buf []byte) (*ChaincodeData, error)
//從檔案系統中獲取ChaincodeData，即buf, err := GetChaincodePackage(ccname, ccversion)和_, err = ccpack.InitFromBuffer(buf)
func (ccpack *CDSPackage) InitFromFS(ccname string, ccversion string) ([]byte, *pb.ChaincodeDeploymentSpec, error)
//ccpack.buf寫入檔案，檔名為/var/hyperledger/production/chaincodes/Name.Version
func (ccpack *CDSPackage) PutChaincodeToFS() error
//程式碼在core/common/ccprovider/cdspackage.go
```

### 3.5、CCContext結構體

```go
type CCContext struct { //ChaincodeD上下文
    ChainID string
    Name string
    Version string
    TxID string
    Syscc bool
    SignedProposal *pb.SignedProposal
    Proposal *pb.Proposal
    canonicalName string
}

//構造CCContext
func NewCCContext(cid, name, version, txid string, syscc bool, signedProp *pb.SignedProposal, prop *pb.Proposal) *CCContext
//name + ":" + version
func (cccid *CCContext) GetCanonicalName() string
//程式碼在core/common/ccprovider/ccprovider.go
```

## 4、chaincode目錄相關實現

### 4.1、ChaincodeProviderFactory介面定義及實現

#### 4.1.1、ChaincodeProviderFactory介面定義

```go
type ChaincodeProviderFactory interface {
    //構造ChaincodeProvider例項
    NewChaincodeProvider() ChaincodeProvider
}

func RegisterChaincodeProviderFactory(ccfact ChaincodeProviderFactory) {
    ccFactory = ccfact
}
func GetChaincodeProvider() ChaincodeProvider {
    return ccFactory.NewChaincodeProvider()
}
//程式碼在core/common/ccprovider/ccprovider.go
```

#### 4.1.2、ChaincodeProviderFactory介面實現

```go
type ccProviderFactory struct {
}

func (c *ccProviderFactory) NewChaincodeProvider() ccprovider.ChaincodeProvider {
    return &ccProviderImpl{}
}

func init() {
    ccprovider.RegisterChaincodeProviderFactory(&ccProviderFactory{})
}
//程式碼在core/chaincode/ccproviderimpl.go
```

### 4.2、ChaincodeProvider介面定義及實現

#### 4.2.1、ChaincodeProvider介面定義

```go
type ChaincodeProvider interface {
    GetContext(ledger ledger.PeerLedger) (context.Context, error)
    GetCCContext(cid, name, version, txid string, syscc bool, signedProp *pb.SignedProposal, prop *pb.Proposal) interface{}
    GetCCValidationInfoFromLSCC(ctxt context.Context, txid string, signedProp *pb.SignedProposal, prop *pb.Proposal, chainID string, chaincodeID string) (string, []byte, error)
    ExecuteChaincode(ctxt context.Context, cccid interface{}, args [][]byte) (*pb.Response, *pb.ChaincodeEvent, error)
    Execute(ctxt context.Context, cccid interface{}, spec interface{}) (*pb.Response, *pb.ChaincodeEvent, error)
    ExecuteWithErrorFilter(ctxt context.Context, cccid interface{}, spec interface{}) ([]byte, *pb.ChaincodeEvent, error)
    Stop(ctxt context.Context, cccid interface{}, spec *pb.ChaincodeDeploymentSpec) error
    ReleaseContext()
}
//程式碼在core/common/ccprovider/ccprovider.go
```

#### 4.2.2、ChaincodeProvider介面實現

```go
type ccProviderImpl struct {
    txsim ledger.TxSimulator //交易模擬器
}

type ccProviderContextImpl struct {
    ctx *ccprovider.CCContext
}

//獲取context.Context，新增TXSimulatorKey繫結c.txsim
func (c *ccProviderImpl) GetContext(ledger ledger.PeerLedger) (context.Context, error)
//構造CCContext，並構造ccProviderContextImpl
func (c *ccProviderImpl) GetCCContext(cid, name, version, txid string, syscc bool, signedProp *pb.SignedProposal, prop *pb.Proposal) interface{}
//呼叫GetChaincodeDataFromLSCC(ctxt, txid, signedProp, prop, chainID, chaincodeID)獲取ChaincodeData中Vscc和Policy
func (c *ccProviderImpl) GetCCValidationInfoFromLSCC(ctxt context.Context, txid string, signedProp *pb.SignedProposal, prop *pb.Proposal, chainID string, chaincodeID string) (string, []byte, error)
//呼叫ExecuteChaincode(ctxt, cccid.(*ccProviderContextImpl).ctx, args)執行上下文中指定的鏈碼
func (c *ccProviderImpl) ExecuteChaincode(ctxt context.Context, cccid interface{}, args [][]byte) (*pb.Response, *pb.ChaincodeEvent, error)
//呼叫Execute(ctxt, cccid.(*ccProviderContextImpl).ctx, spec)
func (c *ccProviderImpl) Execute(ctxt context.Context, cccid interface{}, spec interface{}) (*pb.Response, *pb.ChaincodeEvent, error)
//呼叫ExecuteWithErrorFilter(ctxt, cccid.(*ccProviderContextImpl).ctx, spec)
func (c *ccProviderImpl) ExecuteWithErrorFilter(ctxt context.Context, cccid interface{}, spec interface{}) ([]byte, *pb.ChaincodeEvent, error)
//呼叫theChaincodeSupport.Stop(ctxt, cccid.(*ccProviderContextImpl).ctx, spec)
func (c *ccProviderImpl) Stop(ctxt context.Context, cccid interface{}, spec *pb.ChaincodeDeploymentSpec) error
//呼叫c.txsim.Done()
func (c *ccProviderImpl) ReleaseContext() {
//程式碼在core/chaincode/ccproviderimpl.go
```

### 4.3、ChaincodeSupport結構體

ChaincodeSupport更詳細內容，參考：[Fabric 1.0原始碼筆記 之 Chaincode（鏈碼） #ChaincodeSupport（鏈碼支援服務端）](ChaincodeSupport.md)

### 4.4、ExecuteChaincode函式（執行鏈碼）

執行鏈碼上下文中指定的鏈碼。

```go
func ExecuteChaincode(ctxt context.Context, cccid *ccprovider.CCContext, args [][]byte) (*pb.Response, *pb.ChaincodeEvent, error) {
    var spec *pb.ChaincodeInvocationSpec
    var err error
    var res *pb.Response
    var ccevent *pb.ChaincodeEvent

    spec, err = createCIS(cccid.Name, args) //構造ChaincodeInvocationSpec
    res, ccevent, err = Execute(ctxt, cccid, spec)
    return res, ccevent, err
}
//程式碼在core/chaincode/chaincodeexec.go
```

res, ccevent, err = Execute(ctxt, cccid, spec)程式碼如下：

```go
func Execute(ctxt context.Context, cccid *ccprovider.CCContext, spec interface{}) (*pb.Response, *pb.ChaincodeEvent, error) {
    var err error
    var cds *pb.ChaincodeDeploymentSpec
    var ci *pb.ChaincodeInvocationSpec

    cctyp := pb.ChaincodeMessage_INIT //初始化
    if cds, _ = spec.(*pb.ChaincodeDeploymentSpec); cds == nil { //優先判斷ChaincodeDeploymentSpec
        if ci, _ = spec.(*pb.ChaincodeInvocationSpec); ci == nil { //其次判斷ChaincodeInvocationSpec
            panic("Execute should be called with deployment or invocation spec")
        }
        cctyp = pb.ChaincodeMessage_TRANSACTION //交易
    }

    _, cMsg, err := theChaincodeSupport.Launch(ctxt, cccid, spec)
    var ccMsg *pb.ChaincodeMessage
    ccMsg, err = createCCMessage(cctyp, cccid.TxID, cMsg)
    resp, err := theChaincodeSupport.Execute(ctxt, cccid, ccMsg, theChaincodeSupport.executetimeout)
    if resp.ChaincodeEvent != nil {
        resp.ChaincodeEvent.ChaincodeId = cccid.Name
        resp.ChaincodeEvent.TxId = cccid.TxID
    }
    if resp.Type == pb.ChaincodeMessage_COMPLETED {
        res := &pb.Response{}
        unmarshalErr := proto.Unmarshal(resp.Payload, res)
        return res, resp.ChaincodeEvent, nil
    }
}
//程式碼在core/chaincode
```

## 5、platforms（鏈碼的編寫語言平臺）

platforms更詳細內容，參考：[Fabric 1.0原始碼筆記 之 Chaincode（鏈碼） #platforms（鏈碼語言平臺）](platforms.md)

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